The present invention generally relates to a lining material, superior in abrasion-proof property, to be used in sliding portion. Or it relates, also, to an ultrasonic wave driven motor using the lining material in the sliding portion between a rotor and a stator.
A so-called ultrasonic wave driven motor is a piezo-electric member driven motor which uses piezo-electric member vibrations as an excitation portion to cause resonance in the solid by the vibration of the excitation portion so as to convert the vibration into rotation movements. The ultrasonic wave driven motor is characterized in the simplicity of the construction thereof. The wider application thereof is expected in electronic appliances, camera, appliances for medical treatment use and so on. As the ultrasonic wave driven motor converts the ultrasonic wave vibrations into rotating movements or the like, two types of mediums which come into contact against each other come into friction without fail in the converting portion from the vibration movements into the rotating movements or the like. There is proposed Japanese Laid-Open Patent Application Tokkaisho No. 60-200778 or the like that in the conventional ultrasonic wave driven motor, there are used metals, which are hard with abrasion-proof and tenacity therein, such as steel, hardened steel, tool steel; further non-ferrous metals, which are duralumin, titanium alloy, Monel metal, phosphor bronze, beryllium copper, tungsten, chronium, cobalt, and alloys thereof, as a stator portion for causing resonance by the excitation portion, while there are used metals, which are lower in hardens than metals used in the stator portion, such as copper, copper alloy, aluminum, aluminum alloy, zinc, zinc alloy, as a material of a rotor portion with respect to it, with a lining material made of rubber or phenol resin being disposed in the contact portion between the stator portion and the rotor portion. An ultrasonic wave driven motor of such a construction as described hereinabove has advantages in that the absorption factor of the ultrasonic wave vibrations is extremely small and the Q value of the resonance portion is higher within the range of the working frequency (approximately 20 KHz through 100 KHz.)
But such ultrasonic wave driven motor as described hereinabove has disadvantages in that the abrasion amount of the abrasion portion of the lining material is large, the service life is short, also larger noises are caused in the sliding portion when the lining material has been slid.